As a real digital broadcasting period has recently started, video signals and audio signals in a digital shape have been provided to allow viewers to enjoy clearer and more vivid image quality and multi-channel sound.
Also, data broadcasting constituted by graphics and characters-centered additional data has been recently provided to provide diverse information to viewers. Here, the data broadcasting is provided separately from the present broadcasting program that is currently viewed by a user.
By way of one example of the data broadcasting, program information to be processed, time information, and caption information for hearing-impaired person are provided for all channels. Also, a two-way communication is available to provide diverse additional functions that enable for the user to enjoy shopping while viewing the program.
In such data broadcasting, an update process of the data broadcasting according to an Advanced Common Application Platform (ACAP) standard is performed in real time through Application Information Table (AIT) and Digital Storage Media-Command and Control (DSM-CC) data transmitted from a broadcasting station.
The AIT and DSM-CC are data transmitted to a transport stream of DTV. The AIT has information on whether the data broadcasting exists and updates information. DSM-CC has data (for example, picture and font) control information of the substantial data broadcasting.
As the data broadcasting is provided as described above, a broadcasting view type is changed from a type that a user views a program transmitted one-sidedly from a broadcasting station to a selective broadcasting view type that a user selects and views the provided programs.
Also, the data broadcasting includes diverse sorts of additional information such as news, weather, home shopping, stock information, games and traffic situations, such that the user can select only his or her desired specific additional information of the diverse sorts of additional information and obtain the information thereof.